1 Gallon 1/4 inch Horticultural Charcoal (4 Dry Quarts)

U$D 22.75


1/4 Inch Horticultural Charcoal is a soil ingredient with amazing CEC properties. 5-10 percent of most fast draining potting soils should can charcoal.

Horticultural charcoal is a trusted soil amendment for many bonsai and succulent growers. Charcoal has an amazing ability to absorb moisture / nutrients and release them slowly over time. It has a pH of 7.7 and can be used to reduce acidity in your potting mix. It's a lightweight and chunky ingredient that which improves drainage and aeration. No more than 10 percent of your soil mix should contain charcoal. A little goes a long way.

Bonsai Jack bonsai charcoal is free of chemicals and additives that are often found in store bought cooking charcoal. Screened to 1/4 of an inch before shipping.

Did you know?
All of our soil products are state inspected and tested on a regular basis in order to comply with multi-state regulations.
This ensures you receive material free of dangerous pathogens that can damage or kill plants. This is also required to maintain six nursery stamps that allow us to ship to all 50 states.


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GTIN 00857206008510 SKU: 857206008510 Category:

Additional information

Weight 3 lbs
Dimensions 10 × 8 × 5 in


Country of Origin(COO)

United States

Average Particle Size

1/4 Inch

Minimum Particle Size

1/8th Inch

Maximum Particle Size

3/8ths Inch

Raw Material

Fired Oak and Hickory.


1, Dry

Cubic Inches


Cubic Feet



One Gallon Bag

Plant Type

Soil Conditioner


Dye-free. Chemical free

Bulk Density

.137 ounces per cubic inch



Conversations ...

  1. Phil

    Clicked on Discussion, the review field came up. Apologies if this is posted as a review. Feel free to edit and move this, if appropriate.

    I have questions about the charcoal.

    I read the description, was wondering:
    1) Why recommend no more than 10% of a mix to be charcoal?
    2) What’s the water holding, maybe compared to your pumice, Monto Clay ®, and red lava?
    3) What’s a good ballpark longevity, given no freeze/thaw, container growing?

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    Something wrong with this post? Thanks for letting us know. If you can point us in the right direction...

    • Bonsai Jack

      Hello Phil. Thanks for the message. I will try to cover all of the questions here as best I can. We do not recommend more than 10 percent for several reasons.

      Advice: We have yet to see a professional bonsai master mix that contains more than 10 percent.

      Weight: Bulk density is .137 ounces per cubic inch compared to lava for example that is about .40. Charcoal will easily be washed out of the pot if not weighed down with heavier product.

      Hardness: Charcoal breaks down easily. Here in Florida I would expect it to last about 2 years in a potted plant environment. In general, its not good to have too many particles that will break down as it can decrease drainage. A little is fine. This is why you will not find a lot of Akadama in our part of the world. Akadama will turn to mud within weeks in the Florida climate.

      pH: Its an alkaline product with a pH of 7.7. This affects the overall soil acidity. Charcoal is an interesting material and is difficult to predict. Adding 10 percent less for example will not necessarily increase acidity by ten percent. As I recall in testing a little bit will have the same affect as a lot in terms of soil acidity. I recall this being different that every other particle tested.

      You asked about moisture retention. Charcoal, in our tests, would absorb 94 percent of its weight over 24 hours and release about half of that over 48 hours.
      Charcoal has amazing CEC properties. It’s not possible to test ¼ inch particles for CEC but we know its high because of the general properties of charcoal and the absorption. Only fir and pine bark will absorb more water. No other hard particle aggregate will not come close.

      I hope this helps and didn’t confuse the situation. You are free to use what you want in your own mix. We can only offer suggestions. The best advice is to seek out a local bonsai nursery using our nursery locator tool for advice. Find the guy with the nicest trees in your zone and ask what he is using.

      Have a great week


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